From 34fe5a1cf95c3f114068fc16d919c9cf4b00e428 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Mon, 6 Jul 2020 11:45:07 -0600 Subject: ipv6: fib6_select_path can not use out path for nexthop objects Brian reported a crash in IPv6 code when using rpfilter with a setup running FRR and external nexthop objects. The root cause of the crash is fib6_select_path setting fib6_nh in the result to NULL because of an improper check for nexthop objects. More specifically, rpfilter invokes ip6_route_lookup with flowi6_oif set causing fib6_select_path to be called with have_oif_match set. fib6_select_path has early check on have_oif_match and jumps to the out label which presumes a builtin fib6_nh. This path is invalid for nexthop objects; for external nexthops fib6_select_path needs to just return if the fib6_nh has already been set in the result otherwise it returns after the call to nexthop_path_fib6_result. Update the check on have_oif_match to not bail on external nexthops. Update selftests for this problem. Fixes: f88d8ea67fbd ("ipv6: Plumb support for nexthop object in a fib6_info") Reported-by: Brian Rak Signed-off-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/route.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 82cbb46a2a4f..ea0be7cf3d93 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -431,9 +431,12 @@ void fib6_select_path(const struct net *net, struct fib6_result *res, struct fib6_info *sibling, *next_sibling; struct fib6_info *match = res->f6i; - if ((!match->fib6_nsiblings && !match->nh) || have_oif_match) + if (!match->nh && (!match->fib6_nsiblings || have_oif_match)) goto out; + if (match->nh && have_oif_match && res->nh) + return; + /* We might have already computed the hash for ICMPv6 errors. In such * case it will always be non-zero. Otherwise now is the time to do it. */ -- cgit v1.2.3